The role of growth factors for neovascularization of CNS tumor

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1) Expression of VEGH, VEGFR and VEGFmRNA in human and rat brain tymumor.Vascular endothelial growth factor (VEGF) is a secreted angiogeneic regulator or growth factor of blood vessels during embryonic development and in tumors. We performed expression of VEGF, VEGFR - 1 and VEGFmRNA in human and rat brain.To evaluate to the role of VEGF in the development of vacular system in tumor, and the effects of the microcircumstance, we analyzed existence VEGF, VEGFR(flt-1) and expression of VEGF mRNA using immunohistochemistry and in situ hybridization in human brain tumors and rat trasnsplanted tumors. We used surgically removed astrocytic tumors and metastatic tumors, subcutaneous and intracerebral transplanted animals with ENU induced rat glioma cultured cell (C6). In astrocytic tumors and metastatic tumors, expression of VEGF and VEGER were recognized in newly-formed micro blood vessels which form glomeruloid proliferations. But no expression in endothelial cells without glomeruloid prolif … More erations. In transplanted tumors, no significant differences of proliferative activities of tumor cells and the morphlogy of newly-formed micro blood vessels were identified in each tumors. No glomeruolid proliferations were noted in newly formed micro blood vessels in both tumors.Expression of VEGF and VEGFR were recognized in the endothelial cells but no expression of VEGF mRNA. In cerebral tumor, tumor infiltrations were noted in perivascular infilatrarions was recognized in subcutaneous tumor, pseduopalisading patterns were recognized in the subcutaneous ones and the expression of VEGF mRNA were increased in the tumor cells of pseudopalisading areas. The transplanted tumors were though to be affected by of transplanted areas. The biological and morpholgical characteristics the transplanted tumors were thought to be affected by the microcircumstance of transplanted areas.2) Expression in VEGF, VEGFR, and VEGFmRNA in rat vasculognesis.To evaluate to the role of VEGF in the development of vascular system in normal physiological state, we were analyzed the existence VEGF and expression of VEGF mRNA using immunohistochemistry and in situ hybridization in newborn rats. 24 newborn rat brains were surgically removed at 1, 3, 5, 7, 10 and 14 days after the birth. The expression of VEGF mRNA was recognized in the endothelial cells of capillaries from one day to the 7 days after the birth, the maximum expressions were demonstarated at 10 days. The expression is decreased at 10 days and no expressions are recognized at 14 days after birth. VEGFmRNA was up regulated in the neurons of all specmens, especially in Purukinje cells and neuron at hippocampi. Maximal expressions are recognized at 5days after birth and decreased grandually. Immunohistochemical stainngs using anti VEGF monoclonal antibody obtained similar findings these findings highly suggested that autocrine and paracrine signal transduction for the stimulation of the growth of neovasculature were established in rat vasculogenesis.3) The relationship of tight junction related protein and tumor proliferative actoivities.To elucidate the neovasculature of brain tumors preserve the blood brain barrier (BBB) functions, we studies the expressions of the MDR1 gene products, P-glycoprotein(PgP) and tight juinction related protein. Zo-1 using immunohistochemistry. 30 brain tumors were examined using an anti PgP and an anti ZO-1 Mab, and comparing the expression of VEGF, VEGFR and PCNA.. Positive reactions for PGP and Zo-1 were recoginzed in the endothelial cells in newly formed micro-blloc vessels in primariy glioma but not those in the meningiomas. Although endothelial cells in newly formed micro-blood vessels of all metastatic carcinomas showed positive reaction; negative reactions were seen in those of the primary carcinomas. Weak reactions for anti PgP and Zo-1 compared to those of endothelial cells forming glomeruloid proliferations in newly formed micro-blood vessles in glioblastomas and at the border of the surrounding cerebral tissue of metastatic carcinomas. The negative relations between positive reactions for BBB related proteins, and the expression of VEGF and the proliferative activities were recognized. These findings suggested that the endothelial cells in newly formed micro-blood vessels preserved the fundtions of BBB. Less